Closure for a bottom pour metallurgical ladle



June 4, 1968 J. NADRICH ET AL. 3,386,633

CLOSURE FOR A BOTTOM POUR METALLURGICAL LADLE Filed April 20, 1966 F I 3INVENTORS JOHN NADRICH BY JOHN A. ERICSON ZTTORNEY V FIG. 2

United States Patent 3,386,633 CLOSURE FOR A BOTTSM POUR METALLURGICALLADLE John Nadrich, 2937 Roy St. 44509, and John A. Ericson, 732 MarketSt. 44502, both of Youngstown, Ohio Filed Apr. 20, 1956, Ser. No.544,009 Claims. (Cl. 222-648) ABSTRACT OF THE DISCLOSURE A valve andnozzle assembly for a bottom pour metallurgical ladle which can becontrolled from below the ladle without the use of the usual refractoryshield stopper rod. The nozzle has a pair of spaced concentric annularwells in its top surface with a discharge port extending downwardly fromthe lower surface of the inner well. The valve element is bell-shapedwith its skirt portion fitted into the inner well. The valvin'g elementis rotated by a rod extending downwardly through the nozzle on the axesof the wells and has a notch in its skirt portion which is rotated intoand out of registry with the discharge port thus opening and closing thevalve.

This invention relates to metallurgical apparatus and more particularlyto an improved valve arrangement for controlling the discharge of moltenmetal through the bottom of a ladle containing the same. Accurate andreliable control of this downward discharge of molten metal is anecessity in various metallurgical practices such as the filling ofingot molds and the controlled filling of tundishes in continuouscasting, for example. it is common practice to utilize movable ladliesin transferring molten metal from producing and/or storage facilities tothe place of utilization but severe problems now arise in connectiontherewith particularly due to the large t'onnages of the heats handledand in some cases to the fact that the ladles are subjected to morecontinuous use as in connection with the new oxygen furnaces, forexample.

It is necessary, on the one hand, to so construct the ladle dischargevalve apparatus that the excessive application of heat does not weakenthe operative elements thereof beyond their capabilities but of equal orperhaps more importance is the necessity of avoiding solidification orfreezing of the metal between the coactin'g parts of the valve or in orabout the interstices through which the metal flows downwardly andoutwardly when the valve is opened for pouring.

It is the primary object of the present invention to provide for thepractical solution of the above outlined difficulties, and the same isaccomplished by the novel arrangements and features to be hereinaftermore fully explained and described. The first of the more importantaspects of the invention is the positioning of the valving surfaces andthe inlet to the discharge bore so that the same always remain in anenvironment of fluid metalnot affected by the solidification of metal orthe formation of skulls which invariably takes place during filling ofthe relatively cool ladle, during the continuous exposure of exteriorsurfaces of the ladle to the lower ambient temperature of theatmosphere, and during the open and closing of the discharge valve. Thisis accomplished by re moving such surfaces and the entry portion of thedischarge bore from areas or zones in which solidification or theformation of skulls is more likely to take place. In the apparatusherein disclosed we provide, in effect, an outer well and an inner wellin the bottom of the ladle with the valve sealing surfaces and the fluidmetal discharge point positioned in or adjacent to the inner well whichconsistently remains at a higher temperature than the outer well or themetal contained therein during filling, teeming, etc.

Patented done i, 1958 "ice While it is desirable to control theactuation of the m etal outlet valve from the bottom of the ladle theproblems heretofore encountered in connection therewith have generallyrendered this arrangement impractical and, consequently, the usualpractice is to employ a vertically elongated and refractory protectedstopper rod which extends downwardly through the pool of molten metaland is operated from above while having a lower sea-ling head whichcoacts with the inlet opening of a bore extending downwardly through adischarge nozzle cemented into the bottom wall of the ladle. However,when dealing with steels having higher fluidity or higher temperature orwith large tonnage heats or in situations where the teeming or pouringperiods are quite extended these elongated rods become weak and bent andthe problem is aggravated by erosion of the valve sealing surfaces andin some designs by the tendency of the metal to freeze on such surfaces.The present invention, however, provides such novel improvements in thevalving arrangement and in the valve actuating arrangement that bottommanipulation of the valve is made entirely practical, eliminating anyneed for the elongated stopper rod above described.

Another object of the invention is the provision of an improvedarrangement for attaining an effective seal between the fixed andmovable valving elements of the discharge nozzle, the improved sealbeing operative both during the filling and teeming of the ladle andduring subsequent actuations of the movable element of the valve. Thisis accomplisheld, in accordance with our invention, by utilizing a novelsealing composition between the fixed and movable elements of the valve,which composition is applied in the preparation of the ladle to receivea heat of molten steel.

A further object of the invention is the provision of an improvedmechanical arrangement and configuration of the essential parts of thevalve having the above outlined characteristics and comprised of thefixed discharge nozzle and movable valving head whereby these componentsmay be more easily broken out of the ladle at the end of a heat pour andreplaced with new components, it being well understood by those skilledin the art that it is common practice to replace these componentsbetween the pouring of successive heats.

While the present invention facilitates bottom control of the movablevalving element as explained above many of the features of the inventionmay be advanageously used in conjunction with vertically elongatedstopper rods extending down through the molten steel in the ladle if itis desired, for any reason, to control the bottom pouring from the topof the ladle. The specific aspects of this feature will appear below.

The above and other objects and advantages of the invention will becomeapparent upon. consideration of the following specification andaccompanying drawing wherein there is disclosed a preferred embodimentof the invention.

In the drawing:

FIGURE 1 is a fragmentary vertical section through the bottom portion ofa ladle showing the bottom pour discharge valve of my invention; and

FIGURES 2 and 3 are horizontal sections taken along the lines IIII andIII-III of FGURE l.

The ladle shown is, in accordance with usual practice, comprised of anouter boilerplate cup-like shell 1% which is lined at its bottom 11 withrefractory brick and along its sides with suitable refractory brick orother material shown at 12. The bottom wall of the metal sheath ill islargely apertured at 13, and the bottom lining 11 is also apertured inalignment therewith. The bottom wall is formed with an inner lining Mwhich may be either integral with or separate from the lining 11,depending on preference, and this interlining 14 has a large aperture l5concentric about the aperture 13. Also, the upper edge portion of theaperture is skived or coned outwardly in an upward direction as shown at16.

Seated within the apertures 13 and 15 is a discharge nozzle structure,designated generally by reference numeral 1'7, and having an outwardlydisposed flange which rests on a ledge on the upper surface of thelining 11 radially within the aperture 15. Nozzle 17 is also supportedby a metal disk 18 detachably secured to and supported by the bottomwall of the sheath It) by the bolts 19, for example. It should be notedthat the center portion of the disk 18 is deeply dished in an upwarddirection, as shown at 26, for a purpose to be later explained. Thebottom surface of the nozzle 17 is accurately formed to fit snugly overthe upward protubering portion 20 of the disk 18. The upper peripheraledge portion of nozzle 17 is coned inwardly, as shown at 21, to formwith the surface 16 of the inner lining 14 a deep annular groove, thefunction of which will be explained in detail below.

Nozzle 17 is formed with a centrally disposed thrubore 22 which isaligned with an aperture formed in the raised portion 20 of the disk 18,and immediately outward of this bore 22, in a radial direction, thenozzle 17 is formed with a dome-shaped portion 23, the lower surface ofwhich terminates in a deep rounded annular groove 24, the radial outwardedge of which is spaced inwardly from the conical surface 21, as shownin FIG- URE 1. Connected to and extending vertically downward from thebottom of the groove 24 is at least one hot metal discharge bore 25which is or are aligned with one or more apertures 26 of slightly largerdiameter formed in the disk 18. Radially outward of the groove 24 at thelocation of each bore 25 is a trough 27 formed in the top surface of thenozzle 17, and it is preferable that the bottom of this trough as itleaves the groove between surfaces 16 and 2]. be at the elevation of theupper surface of the inner lining 14.

It will be understood that in accordance with usual practice the nozzle17 Will be molded from a pliant refractory clay and then dried and firedto a hard dry mass suitable for rough handling and for being installedin the ladle preparatory to the tapping of a heat of molten metal intothe ladle At this time the stopper head or valve, to be hereinafterdescribed, is not yet placed in position and it is a simple matter tothen drop the nozzle into position against the disk 18 and into thespace within the apertures of the liners 11 and 14 from which space apreviously used nozzle has been ejected upwardly. To facilitate suchejection or removal of a spent nozzle the disk 18 may be provided withother apertures 28 through which heavy ejection rods may be inserted.After installation of a new nozzle, a small quantity of refractorycement 29 may be wiped into the bottom of the annular interstice betweenthe surfaces 16 and 21 to seal the bottom of the groove formed therebyagainst leakage of hot molten metal.

The stopper head or movable valve member of the assembly is amushroom-shaped body 29 preferably made of graphite to withstand theheat and forces applied to it during filling of the ladle and duringsubsequent opening and closing of the discharge port or parts therefrom.The head 29 has lower and inner surfaces to closely cornplement theshape of the groove 24 and the shape of the outer surface of thedome-shaped center portion of the nozzle 17, all as shown in FIGURE 1.Also, an enlarged threaded bore 30 is formed centrally in the upperportion of the head 29 to receive the flared head 31 of an operatingstem 32, this head being well recessed in the body of the head 29 andprotected by a refractory cap 33 received in the threads 30. As shownmore clearly in FIG- URE 3, the flared head of stem 32 comprisesintegral wedge-shaped vanes 34, and in the process of manufacture of thehead 29 suitable deep grooves are formed in the head 29 to receive thesevanes. By this arrangement, a very heavy turning force may be appliedthrough the 4 stem 32 to the head 29 to insure rotation of the lattereven under very adverse conditions when opening and closing off thedischarge port or ports 25.

To open the port or ports 25 to allow downward discharge of molten metalwhen the head 29 is properly aligned in angular relation to the port orports, we provide an inclined slot 35 in the bottom edge of the head 29at each port location. The slot or slots 35 are then coincident with thetrough of troughs 27 and a passage or passages is thus establishedleading from the space within the ladle to the discharge port or ports25. It will be obvious from FIGURE 1 that upon rotation of the head 29from the position shown in FIGURE 1 continuous portions of the roundeddepending bottom end of the head 2? will bridge the outlet or outlets ofthe trough or troughs 27 and thereby seal oi? the ports from the spacewithin the ladle.

Interposed between the surfaces 23 and 24 of the nozzle structure 17 andthe lower interior surfaces of the head 29 is a layer of cementitiousmaterial 36 which is applied during the assembly of the head to thenozzle. The material 36 is a mixture of fine silicon sand, powderedalumina and a stony powder of sodium or potassium silicate, the lattercommonly known as water glass and as the mixture is shipped to the userit may be either dry or wetted with water to provide a thin paste-likecomposition suitable for immediate use by the preparer of the ladlebottom.

In a dry state the alumina may comprise approximately 25 to 30% of thetotal weight of the ingredients of the composition. This composition, ofcourse, spread onto the surfaces 23 and 24 in a uniform coating beforethe head 29 is fitted, and during the process thereof and shortlythereafter will tend to dry out to a solid or semi-solid state toprovide adequate support for the head 29 as the heavy molten steel lateris filled into the ladle. This avoids premature outward extrusion of thecementitious material 36 and insures the effective sealing of the groove2 particularly at the outlet passages 27, 35. The composition of thematerial 36, however, has the advantageous characteristic of becomingsemi-liquid and thus somewhat slippery after a shorten exposure to theheat of the molten metal and the absorption of heat therefrom into theinterstice occupied by the material. This is due to the softening of thewater glass and perhaps some melting of the silica but, in any event,the end result is to lessen the adhesion and friction between the nozzleand head, permitting the latter to readily rotate with respect to thenozzle to open and close the discharge port or ports while yet providingan effective seal when the valve is closed off.

As shown, the body portion of the stem 32 immediate ly below the vanes34 are longitudinally ribbed to space this body portion slightlyradially inward from the bore 22 to retard heat conduction to this bodyportion and thereby render it more stable and stronger over long periodsas is required in the pouring of large heats into molds and the fillingof tund-ishes in continuous casting plants. Obviously, the diameter ofthe bore 22 is sufficient to accommodate the rotation of the ribs on thestem 32. The stem 32 extends downwardly through an aperture in theraised portion 20 of the plate 18 and is threaded in its lower halfportion as shown at 37. An expansion spring 46 adjustable by a nut isprovided to yieldably bias the head 29 to lower seated position wherebythe valve seal is maintained against the tendency of the heavier steelto float the head 29 upwardly.

Spanning the opening to the projection 20 and rigidly connected to theplate 18 is a bar 42 having a centrally disposed and preferablythickened section 38 through which the stem 32 extends. Safety nuts 43and 44 are threaded onto the stem 32, 37 on opposite sides of thesection 3% to restrain undue raising or lowering of the head 29 in theevent of any serious malfunctioning of the apparatus. Stem 32 andconsequently the head 29 may be arranged to be rotated by an elongatedlever '39 which is keyed onto the lower end of stem 32 as shown at 40,being held in position by a retaining nut 41. If desired, however, thevalving head 29 may be rotated from above by a refractory protectedstopper rod, not shown herein, which may be advantageously connectedinto the threaded bore 30.

Among the more important aspects of the invention is the provision ofthe angular well formed by the surfaces 16 and 21 outwardly of thegroove 24. When hot molten metal is first poured into a relatively coolladle it has the tendency to solidify against the outer wall and moreparticularly against the bottom wall of the ladle, thereby forming whatis known in the art as a skull. In the structure of the presentinvention, however, this tendency to freeze in a radially inwarddirection is stopped by the aforesaid angular well thereby retaining thefluidity or the metal in and about the groove 24 and particularly at thevalving passages 27 and 35. The condition is aided by the proximity ofthese various surfaces and passages to the hot center core of the massof molten metal in the ladle. Consequently, the valve remains readilyoperable throughout the whole of the pouring or teeming cycle and thereis no tendency of the movable head 29 of the valve from becoming frozento or sticking to the nozzle structure 17 which would obviously causeditriculty and increase the probability of malfunctioning of theoperating mechanism for the valve.

Another important aspect of the invention is the integral protuberance20 on the plate or disk 18 which is generally open to the atmosphere sothat the whole of the plate or disk is kept at a safe temperature foradequate strength whereby the bulk of the stem 32 is likewise adequatelycooled for adequate strength and longevity of this part. Finally, thearrangement raises the critical portions of the nozzle assembly 17 wellup into the hot mass of the molten metal in the ladle to permit theproper functioning of the valve in the manner outlined above. Also, theconfiguration of the seal formed by the cementitious material 36effectively resists flow or leakage of molten metal into contact withthe stem 32 which would be highly deleterious to the latter as will beappreciated by those skilled in the metallurgical art. Such resistanceto flow or leakage continues even after repeated opening and closing ofthe valve, this characteristic being aided by the lubricating nature ofthe material 36 as explained above.

Having thus described our invention what we claim is:

1. In a bottom pour meltallurgical ladle having a refractory linedbottom wall and means in the bottom wall providing a downwardly openingdischarge port, the improvement comprising: an annular well in saidbottom wall adjacent to and communicating with said discharge port; anannular valving element for opening and closing said port, the lowersurface of said valving element being complementary to said annular welland received F therein; means to move said valving element effecting theopening and closing of said port; and a second annular well in saidbottom wall spaced radially outward from said valving element and saidfirst mentioned annular well.

2. Apparatus according to claim 1 further characterized in that saidvalving element is provided with a notch in its side portion which maybe brought into and out of registry with said discharge port by movementof said valving element in said first mentioned annular well.

3. Structure according to claim 1 further characterized in that saidfirst mentioned annular well and said discharge port are incorporated ina. nozzle member which is separate and removable from a general bottomlining of the ladle.

4. Structure according to claim 3 further characterized in that saidvalving element has a dependent, thickened and rounded skirt portionwhich has close fitting interengagement with said first mentioned well,the material of said nozzle member being domed upwardly radially withinsaid first mentioned annular well and said valving element beingrecessed upwardly radially inward of said skirt to complement theupwardly projecting domed portion of said nozzle member.

5. Apparatus according to claim 3 further characterized in that saidvalving element is rotatable with respect to said nozzle member aboutthe center axis of said first mentioned well and in that said portcomprises an opening through said nozzle member depending from saidfirst mentioned well while the said means to open and close said portcomprises a notch in said skirt adapted to be brought into registry witha notch in said nozzle member extending radially outward from said firstmentioned well.

6. Apparatus according to claim 3 further characterized in that saidfirst mentioned annular well and said discharge port are incorporated ina nozzle member which is separable and removable from a general bottomlining of the ladle; said general bottom lining being apertured tosnugly receive said nozzle member; and the upper portion of theperipheral edge of said nozzle member and the upper portion of the innerannular wall of said aperture being both skived to form said secondmentioned annular well.

7. Apparatus according to claim 3 further characterized in that saidnozzle member is comprised of a block of refractory material having acentrally disposed and upwardly extending deep recess in its bottomwall; the ladle being provided with a member detachably secured to theouter shell of the ladle for supporting said nozzle member; said memberhaving a configuration complementary to the bottom wall of said nozzlemember.

8. Apparatus according to claim 4 further including a cementitious layerbetween said first mentioned well and the lower portion of said skirtfitting in said well, said cementitious material comprising a mixture ofclay and a silicate which softens upon the continued application of hightemperature to thereby lublicate the relative movement of the valvingelement and the nozzle member while maintaining an effective sealagainst the leakage of molten metal through said port whenever thevalving element is moved to closed position.

9. Apparatus according to claim 5 further including a rotatableoperating stem secured to said valving element and extending downwardlythrough a bore in said nozzle member, and means secured to the lower endof said stem to rotate said stem and consequently said valving element.

10. Apparatus according to claim 9 further characterized in that saidstem has a portion receivable in said bore which is provided withlongitudinally extending ribs whereby the principal body portion of saidstem is spaced from the side wall of the bore to insulate said principalbody portion from the heat of said nozzle member.

References Cited UNITED STATES PATENTS 1,338,001 4/1920 Cordes 251-144 X1,447,021 2/1923 Hamer 251-144 X 1,492,883 5/1924 Kidder 251-144 X1,584,548 5/1926 Karpe 251--310 1,732,126 10/1929 Gardner 251-144 X2,711,846 6/1955 Birchall et a1. 251-310 X 2,286,793 3/1958 Flickingeret a1. 222566 2,961,722 11/1960 Lilljekvist et al. 222567 3,124,8543/1964 Dore 222--1 3,200,457 8/ 1965 Wagstafif 222--1 3,204,836 9/1965Jaffe 222548 WALTER SOBIN, Primary Examiner.

